the balance between chloroplasts & mitochondria that drives a community/ an ecosystem

energy

measure of capacity of a system to do work

work

force through distance

Laws of Thermodynamics

1)energy is neither created nor destroyed (law of conservation

2)energy transfers are never 100% efficient --- when energy is transferred some is lost as heat
*free energy of a system is continually decreasing
*entropy (measure of unusable energy) continually increasing

-most abundant in rocks
--weathering releases phosphate into H20
--plants take up phosphates in H20
----->return it to soil when they die
-phosphates dissolved can be deposited as sediments
-bones high in P (fossils)
-no stable gaseous component @ earth surface temps
--->addition of P to land is slow
--->not well distributed
-humans accelerated P transfer from rocks to soil/plants

carbon cycle facts

-driven by photosynthesis & respiration
--largely run the ecosphere
-most carbon in rocks
-most carbon not in rock is in ocean
-more carbon in atmosphere than in plants
-more carbon in soil than in land plants
-6x more carbon in fossil fuels than in atmosphere
=8x more carbon in fossil fuels than in living plants than

human impact on nitrogen

NOx produced by cars / fertilizers
-we've doubled amt of nitrogen in ecosphere

Niche: "profession" - role in the community
[lions kill zebras--lion niche shaped by others in community]

Habitat: "address" - living space

Competitive Release

when species expands its niche with removal of a competitor
(when species moves away from competitors or a competitor is removed)
ex. increased availability of krill to seals when whale numbers decreased

(looks like carrying capacity)
-rate of predation increases in decelerating fashion up to maximun rate (attained at some high prey density)
-time divided into searching & handling
-DECLINING MORTALITY RATE OF PREY W.INCREASING PREY DENSITY
(as captured prey increases handling time increases & decreases time available for further searching)
-MOST COMMON FOR PREDATORS

factors leading to type III response::
-available of cover to escape from (limited cover protects prey at LOW prey densities only)
-predators search image (if new species appears its not yet recognized as food by predator)
-"switching" (turning to more abundant prey species for food)-depends on food preference

aggregative response

the response of predators to move to areas of high prey density
-reason= predator pop grows slowly compared to prey pop

Optimal foraging theory

-natural selection should favor efficient foragers
-individuals that max their energy/nutrient intake per unit of effort
-time spent foraging balanced against defense time, avoiding predators, searching for mates, caring for young

marginal value theorem

predicts length of time individual should stay in patch before leaving & seeking another

-inseperable from energy flow (productivity usually measured w/ carbon)
-assimilated by plants
-consumed by heterotrophs
-released by both through respiration
-mineralized by decomposers
-accumlated into standing biomass
-withdrawen into long reserves